1. Field of the Invention
The present invention relates to a laminate structure, and more particularly to an extremely thin, highly rigid, and light laminate structure for use as a resin molded article in a portable information terminal device, a portable electronic device, or the like. The laminate structure is composed of two or more different materials and is a structure formed, for example, by performing a metal material plating on a resin.
2. Description of the Related Art
Today, a thinner and shorter resin molded article is demanded for use, for example, in a portable information terminal or an electronic device. However, as long as a conventional resin is used as it is, there is a fear that the flexural rigidity or the impact resistance decreases if the thickness of the resin molded article is reduced. Therefore, it is necessary to newly fabricate a resin molded article whose rigidity or impact resistance does not decrease even if the thickness of the resin molded article is reduced. For that purpose, it is necessary to select a material having a more excellent flexural modulus of elasticity than the conventional molded article material, as well as ensuring the rigidity of the conventional resin molded article. In view of this, various disclosures and proposals are known as methods for raising the rigidity of the molded article as well as reducing its thickness and weight.
(1) Japanese Unexamined Patent Publication No. Hei 07(1995)-60777 discloses use of a metal material or a reinforced resin material filled with a glass fiber or a carbon fiber as a molded article material. PA0 (2) Japanese Unexamined Utility Model Publication No. Sho 62(1987)-62498 discloses an electromagnetic wave shielding material formed by laminating a thin steel plate through the intermediary of an adhesive applied on at least one surface of a dielectric sheet or an electrically conductive sheet as a molded article material. PA0 (3) "Guidebook For Plating Technique" (published by Tokyo Plating Material Cooperative Association, 1987) discloses use of a metal plating for overcoming the problems inherent in a plastic when the plastic is used in a molded article. PA0 (1) To give an aesthetic appearance to heighten its decorative value; PA0 (2) To improve the corrosion resistance to prolong its life; PA0 (3) To give abrasion resistance and lubricity to maintain a function as a component for a long period of time; PA0 (4) To heighten the electric conductivity; PA0 (5) To heighten the electric and magnetic properties; PA0 (6) To give properties of reflecting and absorbing light; PA0 (7) To give properties such as heat resistance, heat absorption, heat conduction, and heat reflection; and PA0 (8) To utilize it as an auxiliary means in a machining process to contribute to resource saving and reduction of the number of processing steps.
However, the techniques disclosed in the above documents have the following problems.
In the case of (1) mentioned above, a reinforced resin material filled with a glass fiber or a carbon fiber is used as a molded article material. However, the reinforced resin material has a poor fluidity at the time of molding, so that it is difficult to mold it into a thin and complex shape. Also, the reinforced resin material has a lower breaking strain as compared with a base material resin used alone and has a fragile property, so that the impact resistance decreases. Further, the reinforced resin material has an increased weight due to the fiber introduced in the resin material, so that it is difficult to reduce the weight and the material costs are high.
In the case of (2) mentioned above, a thin steel plate can be laminated through the intermediary of an adhesive on a dielectric sheet of a simple shape. However, it is difficult to laminate a thin steel plate on a dielectric sheet of a complex shape, and the laminated thin steel plate is likely to be crinkled. Also, by simply laminating the thin steel plate thereon, the weight may increase, so that a suitable thickness must be defined.
In the case of (3) mentioned above, the applied metal plating is used for the following functional purposes:
The metal plating applied to a plastic for the above-mentioned purposes has a thickness as small as 10 .mu.m (0.01 mm) or less and it merely modifies the resin surface.